Test Cross breeding an individual whose phenotype is known but whose genotype is unknown to an individual with a homozygous recessive genotype can be used to determine the first individuals genotype ID: 594128
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Slide1
Test Crosses and ProbabilitySlide2
Test Cross
breeding an individual whose phenotype is known but whose genotype is unknown to an individual with a homozygous recessive genotype
can be used to determine the first individual’s genotypeSlide3
Test Cross Example
A purple-flowered plant is crossed with a white-flowered plant. Some of the plants in the next generation produce purple flowers and some produce white flowers. What is the genotype of the purple-flowered plant?Slide4
A purple-flowered plant is crossed with a white-flowered plant. Some of the plants in the next generation produce purple flowers and some produce white flowers. What is the genotype of the purple-flowered plant?
Identification of Alleles
P = purple
p = white
Parent Genotype Identification
Purple parent: P?
White parent: ppSlide5
Punnett Square
P
?
p
p
A purple-flowered plant is crossed with a white-flowered plant. Some of the plants in the next generation produce purple flowers and some produce white flowers. What is the genotype of the purple-flowered plant?Slide6
Punnett Square
Pp
P
?
p
p
A purple-flowered plant is crossed with a white-flowered plant. Some of the plants in the next generation produce purple flowers and some produce white flowers. What is the genotype of the purple-flowered plant?Slide7
Punnett Square
Pp
p
P
?
p
p
A purple-flowered plant is crossed with a white-flowered plant. Some of the plants in the next generation produce purple flowers and some produce white flowers. What is the genotype of the purple-flowered plant?Slide8
Punnett Square
Pp
p
Pp
P
?
p
p
A purple-flowered plant is crossed with a white-flowered plant. Some of the plants in the next generation produce purple flowers and some produce white flowers. What is the genotype of the purple-flowered plant?Slide9
Punnett Square
Pp
p
Pp
p
P
?
p
p
A purple-flowered plant is crossed with a white-flowered plant. Some of the plants in the next generation produce purple flowers and some produce white flowers. What is the genotype of the purple-flowered plant?Slide10
A purple-flowered plant is crossed with a white-flowered plant. Some of the plants in the next generation produce purple flowers and some produce white flowers. What is the genotype of the purple-flowered plant?
Genotype of Purple ParentSlide11
Punnett Square
Pp
p
Pp
p
P
?
p
p
A purple-flowered plant is crossed with a white-flowered plant. Some of the plants in the next generation produce purple flowers and some produce white flowers. What is the genotype of the purple-flowered plant?Slide12
Test Cross Example
Punnett
Square
Pp
pp
Pp
pp
P
p
p
pSlide13
A purple-flowered plant is crossed with a white-flowered plant. Some of the plants in the next generation produce purple flowers and some produce white flowers. What is the genotype of the purple-flowered plant?
Genotype of Purple Parent
Pp
HeterozygousSlide14
Probability
the likelihood (“chance” or “odds”) that a specific event will occur
can be expressed as words, percents, or fractions
the chance of flipping a heads on a coin is: 1/2
Probability
=
# of one kind of outcome
total
# of possible outcomesSlide15
Probability Example
Two heterozygous purple-flowered plants are crossed. What is the probability that they will have a white-flowered offspring?Slide16
Two heterozygous purple-flowered plants are crossed. What is the probability that they will have a white-flowered offspring?
Identification of Alleles
P = purple
p = white
Parent Genotype Identification
Heterozygous parent 1: Pp
Heterozygous parent 2: PpSlide17
Punnett Square
P
p
P
p
Two heterozygous purple-flowered plants are crossed. What is the probability that they will have a white-flowered offspring?Slide18
Punnett Square
PP
P
p
P
p
Two heterozygous purple-flowered plants are crossed. What is the probability that they will have a white-flowered offspring?Slide19
Punnett Square
PP
Pp
P
p
P
p
Two heterozygous purple-flowered plants are crossed. What is the probability that they will have a white-flowered offspring?Slide20
Punnett Square
PP
Pp
Pp
P
p
P
p
Two heterozygous purple-flowered plants are crossed. What is the probability that they will have a white-flowered offspring?Slide21
Punnett Square
PP
Pp
Pp
pp
P
p
P
p
Two heterozygous purple-flowered plants are crossed. What is the probability that they will have a white-flowered offspring?Slide22
Probability of White Offspring
Two heterozygous purple-flowered plants are crossed. What is the probability that they will have a white-flowered offspring?Slide23
Punnett Square
PP
Pp
Pp
pp
P
p
P
p
Two heterozygous purple-flowered plants are crossed. What is the probability that they will have a white-flowered offspring?Slide24
Probability of White Offspring
1/4
Two heterozygous purple-flowered plants are crossed. What is the probability that they will have a white-flowered offspring?Slide25
Multiple Events Probability
calculate the probability of two or more things happening in a row by multiplying the probability of each event occurring on its own
Probability of flipping a heads:Slide26
Multiple Events Probability
calculate the probability of two or more things happening in a row by multiplying the probability of each event occurring on its own
Probability of flipping a heads: 1/2
Probability of flipping a tails:Slide27
Multiple Events Probability
calculate the probability of two or more things happening in a row by multiplying the probability of each event occurring on its own
Probability of flipping a heads: 1/2
Probability of flipping a tails: 1/2
Probability of flipping a heads and then a tails:Slide28
Multiple Events Probability
calculate the probability of two or more things happening in a row by multiplying the probability of each event occurring on its own
Probability of flipping a heads: 1/2
Probability of flipping a tails: 1/2
Probability of flipping a heads and then a tails: 1/2 * 1/2 = 1/4Slide29
Two heterozygous purple-flowered plants are crossed. What is the probability that they produce a white-flowered offspring and then produce a purple-flowered offspring?
Identification of Alleles
P = purple
p = white
Parent Genotype Identification
Heterozygous parent 1: Pp
Heterozygous parent 2: PpSlide30
Punnett Square
PP
Pp
Pp
pp
P
p
P
p
Two heterozygous purple-flowered plants are crossed. What is the probability that they produce a white-flowered offspring and then produce a purple-flowered offspring?Slide31
Multiple Events Probability Example
White
Flower
ProbabilitySlide32
Punnett Square
PP
Pp
Pp
pp
P
p
P
p
Two heterozygous purple-flowered plants are crossed. What is the probability that they produce a white-flowered offspring and then produce a purple-flowered offspring?Slide33
Multiple Events Probability Example
White
Flower
Probability
Purple
Flower
Probability
1
4Slide34
Punnett Square
PP
Pp
Pp
pp
P
p
P
p
Two heterozygous purple-flowered plants are crossed. What is the probability that they produce a white-flowered offspring and then produce a purple-flowered offspring?Slide35
Multiple Events Probability Example
White
Flower
Probability
Purple
Flower
Probability
Probability of Getting
BOTH
1
3
4
4Slide36
Multiple Events Probability Example
White
Flower
Probability
Purple
Flower
Probability
Probability of Getting
BOTH
1
*
3
=
4
4Slide37
Multiple Events Probability Example
White
Flower
Probability
Purple
Flower
Probability
Probability of Getting
BOTH
1
*
3
=
3
4
4
16Slide38
In
garden peas, long stems (L) are dominant and short stems (l) are recessive. A long plant is crossed with a
short
plant. This is a test cross to determine the genotype of the long plant. If all of the offspring produced in this test cross are also long plants, what was the genotype of the parental long stem plant?
Identification of Alleles
L = long stems
l = short stems
Parent Genotype Identification
Long stem parent: L?Short stem parent: llSlide39
Punnett Square
L
?
l
l
In garden peas, long stems (L) are dominant and short stems (l) are recessive. A long plant is crossed with a short plant. This is a test cross to determine the genotype of the long plant. If all of the offspring produced in this test cross are also long plants, what was the genotype of the parental long stem plant? Slide40
Punnett Square
Ll
L
?
l
l
In garden peas, long stems (L) are dominant and short stems (l) are recessive. A long plant is crossed with a short plant. This is a test cross to determine the genotype of the long plant. If all of the offspring produced in this test cross are also long plants, what was the genotype of the parental long stem plant? Slide41
Punnett Square
Ll
l
L
?
l
l
In garden peas, long stems (L) are dominant and short stems (l) are recessive. A long plant is crossed with a short plant. This is a test cross to determine the genotype of the long plant. If all of the offspring produced in this test cross are also long plants, what was the genotype of the parental long stem plant? Slide42
Punnett Square
Ll
l
Ll
L
?
l
l
In garden peas, long stems (L) are dominant and short stems (l) are recessive. A long plant is crossed with a short plant. This is a test cross to determine the genotype of the long plant. If all of the offspring produced in this test cross are also long plants, what was the genotype of the parental long stem plant? Slide43
Punnett Square
Ll
l
Ll
l
L
?
l
l
In garden peas, long stems (L) are dominant and short stems (l) are recessive. A long plant is crossed with a short plant. This is a test cross to determine the genotype of the long plant. If all of the offspring produced in this test cross are also long plants, what was the genotype of the parental long stem plant? Slide44
In garden peas, long stems (L) are dominant and short stems (l) are recessive. A long plant is crossed with a short plant. This is a test cross to determine the genotype of the long plant. If all of the offspring produced in this test cross are also long plants, what was the genotype of the parental long stem plant?
Long stem Plant GenotypeSlide45
Punnett Square
Ll
l
Ll
l
L
?
l
l
In garden peas, long stems (L) are dominant and short stems (l) are recessive. A long plant is crossed with a short plant. This is a test cross to determine the genotype of the long plant. If all of the offspring produced in this test cross are also long plants, what was the genotype of the parental long stem plant? Slide46
Punnett Square
Ll
Ll
Ll
Ll
L
?
l
l
In garden peas, long stems (L) are dominant and short stems (l) are recessive. A long plant is crossed with a short plant. This is a test cross to determine the genotype of the long plant. If all of the offspring produced in this test cross are also long plants, what was the genotype of the parental long stem plant? Slide47
Punnett Square
Ll
Ll
Ll
Ll
L
L
l
l
In garden peas, long stems (L) are dominant and short stems (l) are recessive. A long plant is crossed with a short plant. This is a test cross to determine the genotype of the long plant. If all of the offspring produced in this test cross are also long plants, what was the genotype of the parental long stem plant? Slide48
In garden peas, long stems (L) are dominant and short stems (l) are recessive. A long plant is crossed with a short plant. This is a test cross to determine the genotype of the long plant. If all of the offspring produced in this test cross are also long plants, what was the genotype of the parental long stem plant?
Long stem Plant Genotype
LL
Homozygous dominantSlide49
If
a heterozygous long stem plant (L) is crossed with a homozygous recessive short stem plant (l), what is the probability that their offspring will be short stemmed? You may report your answer in a fraction or a
percent.
Identification of Alleles
L = long stems
l = short stems
Parent Genotype Identification
Ll
llSlide50
Punnett Square
L
l
l
l
If a heterozygous long stem plant (L) is crossed with a homozygous recessive short stem plant (l), what is the probability that their offspring will be short stemmed? You may report your answer in a fraction or a
percent.Slide51
Punnett Square
Ll
L
l
l
l
If a heterozygous long stem plant (L) is crossed with a homozygous recessive short stem plant (l), what is the probability that their offspring will be short stemmed? You may report your answer in a fraction or a
percent.Slide52
Punnett Square
Ll
ll
L
l
l
l
If a heterozygous long stem plant (L) is crossed with a homozygous recessive short stem plant (l), what is the probability that their offspring will be short stemmed? You may report your answer in a fraction or a
percent.Slide53
Punnett Square
Ll
ll
Ll
L
l
l
l
If a heterozygous long stem plant (L) is crossed with a homozygous recessive short stem plant (l), what is the probability that their offspring will be short stemmed? You may report your answer in a fraction or a
percent.Slide54
Punnett Square
Ll
ll
Ll
ll
L
l
l
l
If a heterozygous long stem plant (L) is crossed with a homozygous recessive short stem plant (l), what is the probability that their offspring will be short stemmed? You may report your answer in a fraction or a
percent.Slide55
Short
S
temmed Offspring Probability
If a heterozygous long stem plant (L) is crossed with a homozygous recessive short stem plant (l), what is the probability that their offspring will be short stemmed? You may report your answer in a fraction or a
percent.Slide56
Punnett Square
Ll
ll
Ll
ll
L
l
l
l
If a heterozygous long stem plant (L) is crossed with a homozygous recessive short stem plant (l), what is the probability that their offspring will be short stemmed? You may report your answer in a fraction or a
percent.Slide57
Short
S
temmed Offspring Probability
2/4
If a heterozygous long stem plant (L) is crossed with a homozygous recessive short stem plant (l), what is the probability that their offspring will be short stemmed? You may report your answer in a fraction or a
percent.Slide58
Simplify fractions if possible.Slide59
Short
S
temmed Offspring Probability
2/4
If a heterozygous long stem plant (L) is crossed with a homozygous recessive short stem plant (l), what is the probability that their offspring will be short stemmed? You may report your answer in a fraction or a
percent.Slide60
Short
S
temmed Offspring Probability
2/4
1/2 or 50%
If a heterozygous long stem plant (L) is crossed with a homozygous recessive short stem plant (l), what is the probability that their offspring will be short stemmed? You may report your answer in a fraction or a
percent.Slide61
In
garden peas, inflated (I) pods are dominant to constricted pods (
i
). A plant that has inflated pods is crossed with a plant that has constricted pods in a test cross. If all of the offspring produced from this cross have inflated pods, what was the genotype of the parental plant with inflated pods
?
Identification of Alleles
I = inflated pods
i
= constricted podsParent Genotype IdentificationInflated parent: I?Constricted parent: iiSlide62
Punnett Square
I
?
i
i
In garden peas, inflated (I) pods are dominant to constricted pods (
i
). A plant that has inflated pods is crossed with a plant that has constricted pods in a test cross. If all of the offspring produced from this cross have inflated pods, what was the genotype of the parental plant with inflated pods?Slide63
Punnett Square
Ii
I
?
i
i
In garden peas, inflated (I) pods are dominant to constricted pods (
i
). A plant that has inflated pods is crossed with a plant that has constricted pods in a test cross. If all of the offspring produced from this cross have inflated pods, what was the genotype of the parental plant with inflated pods?Slide64
Punnett Square
Ii
I
?
i
i
In garden peas, inflated (I) pods are dominant to constricted pods (
i
). A plant that has inflated pods is crossed with a plant that has constricted pods in a test cross. If all of the offspring produced from this cross have inflated pods, what was the genotype of the parental plant with inflated pods?Slide65
Punnett Square
Ii
i
I
?
i
i
In garden peas, inflated (I) pods are dominant to constricted pods (
i
). A plant that has inflated pods is crossed with a plant that has constricted pods in a test cross. If all of the offspring produced from this cross have inflated pods, what was the genotype of the parental plant with inflated pods?Slide66
Punnett Square
Ii
i
Ii
I
?
i
i
In garden peas, inflated (I) pods are dominant to constricted pods (
i
). A plant that has inflated pods is crossed with a plant that has constricted pods in a test cross. If all of the offspring produced from this cross have inflated pods, what was the genotype of the parental plant with inflated pods?Slide67
Punnett Square
Ii
i
Ii
i
I
?
i
i
In garden peas, inflated (I) pods are dominant to constricted pods (
i
). A plant that has inflated pods is crossed with a plant that has constricted pods in a test cross. If all of the offspring produced from this cross have inflated pods, what was the genotype of the parental plant with inflated pods?Slide68
In garden peas, inflated (I) pods are dominant to constricted pods (
i
). A plant that has inflated pods is crossed with a plant that has constricted pods in a test cross. If all of the offspring produced from this cross have inflated pods, what was the genotype of the parental plant with inflated pods?
Inflated Pods Parent GenotypeSlide69
Punnett Square
Ii
i
Ii
i
I
?
i
i
In garden peas, inflated (I) pods are dominant to constricted pods (
i
). A plant that has inflated pods is crossed with a plant that has constricted pods in a test cross. If all of the offspring produced from this cross have inflated pods, what was the genotype of the parental plant with inflated pods?Slide70
Punnett Square
Ii
Ii
Ii
Ii
I
?
i
i
In garden peas, inflated (I) pods are dominant to constricted pods (
i
). A plant that has inflated pods is crossed with a plant that has constricted pods in a test cross. If all of the offspring produced from this cross have inflated pods, what was the genotype of the parental plant with inflated pods?Slide71
Punnett Square
Ii
Ii
Ii
Ii
I
I
i
i
In garden peas, inflated (I) pods are dominant to constricted pods (
i
). A plant that has inflated pods is crossed with a plant that has constricted pods in a test cross. If all of the offspring produced from this cross have inflated pods, what was the genotype of the parental plant with inflated pods?Slide72
In garden peas, inflated (I) pods are dominant to constricted pods (
i
). A plant that has inflated pods is crossed with a plant that has constricted pods in a test cross. If all of the offspring produced from this cross have inflated pods, what was the genotype of the parental plant with inflated pods?
Inflated Pods Parent Genotype
II
Homozygous dominantSlide73
In
garden peas, axial flowers are dominant and terminal flowers are recessive. In a cross between two homozygous plants, one that has axial flowers and one that has terminal flowers, what will be the probability that they produce an axial offspring then a terminal offspring
?
Identification of Alleles
Parent Genotype IdentificationSlide74
The Work of
Gregor
Mendel
(a little background information…)
Holt Biology, pg. 163Slide75
In
garden peas, axial flowers are dominant and terminal flowers are recessive. In a cross between two homozygous plants, one that has axial flowers and one that has terminal flowers, what will be the probability that they produce an axial offspring then a terminal offspring
?
Identification of Alleles
A = axial flowers
a = terminal flowers
Parent Genotype Identification
AA
aaSlide76
Punnett Square
A
A
a
a
In garden peas, axial flowers are dominant and terminal flowers are recessive. In a cross between two homozygous plants, one that has axial flowers and one that has terminal flowers, what will be the probability that they produce an axial offspring then a terminal offspring?Slide77
Punnett Square
Aa
Aa
Aa
Aa
A
A
a
a
In garden peas, axial flowers are dominant and terminal flowers are recessive. In a cross between two homozygous plants, one that has axial flowers and one that has terminal flowers, what will be the probability that they produce an axial offspring then a terminal offspring?Slide78
Probability of Producing an Axial Offspring followed by a Terminal Offspring
In garden peas, axial flowers are dominant and terminal flowers are recessive. In a cross between two homozygous plants, one that has axial flowers and one that has terminal flowers, what will be the probability that they produce an axial offspring then a terminal offspring?Slide79
Multiple Events Probability Example
Axial
Flower
Probability
Terminal
Flower
Probability
Probability of Getting
BOTH
4
0
4
4Slide80
Multiple Events Probability Example
Axial
Flower
Probability
Terminal
Flower
Probability
Probability of Getting
BOTH
4
*
0
=
4
4Slide81
Multiple Events Probability Example
Axial
Flower
Probability
Terminal
Flower
Probability
Probability of Getting
BOTH
4
*
0
=
0
4
4
16Slide82
Simplify fractions if possible.Slide83
Probability of Producing an Axial Offspring followed by a Terminal Offspring
0
In garden peas, axial flowers are dominant and terminal flowers are recessive. In a cross between two homozygous plants, one that has axial flowers and one that has terminal flowers, what will be the probability that they produce an axial offspring then a terminal offspring?